Projects per year
The stability of the hydroxyl termination and downward band bending on the m-plane (101̅0) and a-plane (112̅0) faces of ZnO single crystals was investigated using synchrotron and real-time X-ray photoelectron spectroscopy. On these nonpolar surfaces, a strong correlation was found between the surface band bending and the surface OH coverage, both of which could be modified via heat treatment in ultra high vacuum (UHV). On the m-plane (101̅0) face, in particular, a threshold temperature of ∼400 °C was observed, after which there was a sudden increase in OH desorption and upward movement of the near-surface bands, resulting in a metallic-to-semiconductor transition in the electronic nature of the surface, with a change from surface electron accumulation to depletion. This loss of surface metallicity is associated with the disruption of a stable monolayer of chemisorbed hydroxyl groups that form a closed hydrogen-bonded network, across rows of Zn–O dimers, on the m-plane (101̅0) face. The surface electron accumulation layers on both the m-plane (101̅0) and a-plane (112̅0) faces can be modified and eventually removed by simple UHV heat treatment, with important implications for the electrical properties of ZnO nanostructures and catalytic ZnO nanopowders, which contain a high proportion of these nonpolar surfaces.
|Number of pages||8|
|Journal||Journal of Physical Chemistry C|
|Early online date||13 Oct 2014|
|Publication status||Published - 26 Oct 2014|
FingerprintDive into the research topics of 'Stability of the Surface Electron Accumulation Layers on the Nonpolar (1010) and (1120) Faces of ZnO'. Together they form a unique fingerprint.
- Faculty of Business and Physcial Sciences, Department of Physics - Professor, Head of Department (Physics)
Person: Teaching And Research, Other
- 1 Finished
Photoelectron Spectroscopy and Microscopy using Synchrotron Radiation for Exploiting Diamond surfaces and Interfaces
Engineering and Physical Sciences Research Council
01 Oct 2009 → 30 Sept 2013
Project: Externally funded research